1. Field of the Invention
The present invention relates to an eccentric stroke adjusting mechanism for use in a power tool and to a power tool per se.
2. Background Art
As illustrated in U.S. Pat. No. 4,744,177 and EP-A-0820838, known abrasive power tools such as sanders and grinders generally comprise a housing, a motor vertically located inside the housing, a principle drive shaft, a working (sanding) plate and an eccentric stroke adjusting mechanism. The eccentric stroke adjusting mechanism is used to adjust the vibration amplitude of the working (sanding) plate to meet different requirements of different workpieces. The eccentric stroke adjusting mechanism comprises an eccentric shaft securely attached to the principle drive shaft, an eccentric driving device and a bearing for connecting the eccentric driving device and the working (sanding) plate. However such an eccentric stroke adjusting mechanism is not easily and reliably balanced and the adjusted eccentricity is easy to displace. Furthermore the eccentric stroke adjusting mechanism can only be applied to adjust single disk working (sanding) plate.